JP2006130454A - Optically trapping device and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optically trapping device which is manufactured easily and has a simple constitution and by which a minute object can be optically trapped/moved and the position of the moved minute object can be observed. <P>SOLUTION: This optically trapping device is provided with: a light source 2 for emitting light; an optical fiber 10 having a core 12 for propagating the light emitted from the light source 2; an optical fiber probe 4 having a light emitting optical probe formed at the tip of the core 12; a sample disk 14 for placing the minute object 15; and a moving means 6 for moving the sample disk 14 relatively to the optical fiber probe 4. The optical fiber probe 4 is formed into a conical shape. The inclined angle of a normal line 20 on a part or the whole of the surface of the optical fiber probe 4 with respect to the optical axis of the propagation light 18 to be propagated through the optical fiber 10 is made smaller than the total reflection angle of the propagation light 18 and larger than zero degree. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical trap apparatus and a method thereof in a nano-micron order minute object manipulation technique, and is particularly suitable for application to a processing / assembly technique based on deposition of nano-micron order minute objects.

In recent years, in various tests and analysis processes in the fields of physics and chemistry that handle fine samples, specific minute objects are captured from minute objects (for example, metals, dielectric fine particles, microorganisms and plant and animal cells) in samples, and arbitrary It is known to use optical trap technology to move to and operate a place (see, for example, Patent Documents 1 and 2).
In Patent Document 1, a variable aperture for narrowing the beam width of a light beam for an optical trap is provided in the optical path, so that capturing and opening of a fine object can be controlled by changing the aperture amount of the variable aperture. There has been proposed a technique related to a fine object operating apparatus that can efficiently perform operations such as capturing and moving a fine object with tweezers.
Further, Patent Document 2 enables optical trapping of minute objects by using light emitted from an optical fiber having a tip-shaped tapered structure at the tip or an optical fiber having a distributed refractive index structure at the core. A technology related to optical tweezers has been proposed.
In addition to the high-resolution measurement using near-field light, by providing an optical fiber probe having a structure that allows the emission light to be collected, an optical fiber probe that realizes a wide range measurement using the emission light (propagation light), optical Detection devices and methods are also being studied.
This optical trap technology captures a minute object in the vicinity of a focused spot position by the optical pressure of the collected light. By this capturing method, a minute object can be captured at a fixed position without contact. It is also possible to move the captured fine object to an arbitrary position in the sample by moving the focused spot.
A general configuration as an optical system constituting the optical trap device is a configuration for trapping light emitted from an objective lens as described in Patent Document 1, for example. For example, in the case of an optical trap device that targets dielectric fine particles, the fine particles are trapped by transfer of light pressure from refracted light incident on the fine particles. A strong light pressure can be obtained by using light emitted from a high NA objective lens.
However, an optical system using an objective lens has a complicated structure and alignment adjustment is difficult. In addition, an objective lens having a high NA (0.6 or more) generally has a working distance of 1 mm or less, but an objective lens having a diameter of at least several mm must be brought close to the sample, and a space for arranging the sample. However, it is necessary to make it large size corresponding to it.
It is not easy to find a target particle having a size of several μm to several nm from a sample of several mm or more. These are factors that make the work more complicated.
Therefore, Patent Document 2 proposes an optical trap device that uses light emitted from the end face of an optical fiber as a device that avoids the disadvantages of an optical trap device using an optical system that uses an objective lens, including the above points. ing.
In Patent Document 2, a condensing spot is formed by condensing the emitted light by forming a tapered tip on the end face of the optical fiber that emits light, or by using an optical fiber having a distributed refractive index structure in the core. Capturing of minute objects in the vicinity is possible.
JP 2001-062792 A JP 09-043434 A

However, in an optical fiber having a tip tapered shape at the tip, the lens effect can be obtained by making the tip into a spherical shape, but it is difficult to manufacture. Similarly, in an apparatus using a fiber having a distributed refractive index structure, it is difficult to control the refractive index distribution at the time of manufacture, and it is difficult to obtain a desired light collecting performance.
Furthermore, in the optical trap device, it is necessary to confirm the position of the minute object after the operation. However, in the observation with a generally used optical microscope, the resolution is becoming insufficient with the recent miniaturization of the operation target.
In particular, when the minute object to be operated is in the nano-order, there has been a problem that the position cannot be confirmed.
Therefore, the present invention has been made in view of the above-described points, and is easy to fabricate and enables a light trap of a minute object, operation, and observation of the position of the minute object after the operation with a simple configuration. It is to provide an optical trap device and a method thereof.

In order to solve the above problems, the invention according to claim 1 is directed to a light source that emits light, an optical fiber that has a core that propagates the light emitted from the light source, and emits light to a tip of the core. An optical trap device comprising: an optical fiber probe on which an optical probe is formed; a sample plate for placing a micro object; and a moving means for moving the sample plate relative to the optical fiber probe. The optical fiber probe has a conical shape, and the inclination angle of the normal line on the surface or the entire surface of a part of the optical fiber probe with respect to the optical axis of the propagation light propagating through the optical fiber is the total reflection angle of the propagation light. Featuring an optical trap device that is less than and greater than 0 degrees.
The invention according to claim 2 is characterized by the optical trap device according to claim 1, further comprising detection means for detecting light emitted from the optical probe onto the sample plate.
The invention according to claim 3 further comprises wavelength control means for controlling the wavelength of light emitted from the light source so that the size of the light spot by the emitted light becomes a desired value. Item 10. An optical trap device according to Item 1.
The invention according to claim 4 is characterized in that light is emitted from a light source, has a conical shape, and a normal is inclined on the surface or the entire surface of a part of the optical probe with respect to the optical axis of propagating light propagating through an optical fiber. A minute object in which the emitted light is propagated to the core of an optical fiber probe whose angle is less than the total reflection angle of the propagating light, and spots based on the propagating light propagated through the core are arranged on the sample plate The optical fiber probe is moved relative to the surface to be measured so as to be close to and away from the surface to be measured so that the minute object is captured, and the optical fiber probe is placed horizontally with respect to the sample plate. It is characterized by an optical trap method in which the minute object is relatively moved with respect to the sample plate by being relatively moved in the direction.
The invention according to claim 5 is characterized in that the wavelength of light emitted from the light source is controlled to a wavelength determined based on the size of the light spot. .

According to a sixth aspect of the present invention, a light source for emitting light, an optical fiber having a core for propagating light emitted from the light source, and an optical probe for emitting light to the tip of the core are formed. An optical trap comprising: an optical fiber probe in which an optical probe is coated with a light-shielding coating layer; a sample plate for placing a minute object; and a moving means for moving the sample plate relative to the optical fiber probe. In the apparatus, the optical fiber probe has a conical shape, and the inclination angle of the normal line on the surface or the entire surface of a part of the optical fiber probe with respect to the optical axis of the propagating light propagating through the optical fiber is the propagation light. An optical trap device having a total reflection angle of less than 0 degree and greater than 0 degree.
The invention according to claim 7 is characterized in that the optical trap device according to claim 6 further comprises detection means for detecting light emitted from the optical fiber probe onto the sample plate.
The invention according to claim 8 is a wavelength for controlling the wavelength of light emitted from the light source so that the light transmittance of the light-shielding coating layer has a maximum value or a wavelength in the vicinity thereof. The optical trap device according to claim 6, further comprising a control means.
The invention according to claim 9 is the optical trap device according to claim 6, wherein the material of the light-shielding coating layer is gold.
The invention according to claim 10 emits light from a light source, has a conical shape, and has a normal line on a part of the surface or the entire surface of the optical probe with respect to the optical axis of propagating light propagating through the optical fiber. The emitted light is propagated to the core of an optical fiber probe formed with an inclination angle less than the total reflection angle of the propagating light and larger than 0 degrees, and the spot based on the propagating light propagated through the core is the spot By moving the optical fiber probe in the direction of approaching and separating from the surface to be measured so as to be formed in the vicinity of the minute object arranged on the sample plate, the minute object is captured and the light The optical trap method is characterized in that the micro object is moved relative to the sample plate by moving the fiber probe relative to the sample plate in the horizontal direction.
In the invention described in claim 11, the wavelength of the light controlled by the wavelength control means is a wavelength having the light transmittance of the light-shielding coating layer as a maximum value or a value in the vicinity thereof. Features an optical trap method.

  According to the present invention, since an optical fiber probe capable of forming a condensed spot of emitted light with a tapered structure is used, it is easy to manufacture and enables a light trap operation of a minute object with a simple configuration. An optical trap device can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a first embodiment of an optical trap device including an optical fiber probe according to the present invention. FIG. 2 is an enlarged view for explaining the shape of the protruding portion of the optical fiber probe shown in FIG.
With reference to FIG.1 and FIG.2, the outline | summary of the photon detection apparatus which is an optical trap apparatus of this Embodiment, and an operation process are demonstrated.
The photodetection device 1 shown in FIG. 1 is applied to, for example, a manipulation device that operates and moves fine particles dispersed in a liquid over a range of several nm to several hundred μm.
1 includes a light source 2 that emits light, a polarization beam splitter 3 that is disposed in the optical path of light emitted from the light source 2, and a light beam that has passed through the polarization beam splitter 3. From the sample plate 14 and the optical fiber probe 4 that collects the light that has passed through the quarter-wave plate 8 disposed in the optical path and irradiates the fine particles 15 in the dispersion 16 disposed on the sample plate 14. And a photodetector 5 for detecting the return light.
The light source 2 oscillates light based on drive power received via a power supply device (not shown). The output control unit 7 performs output switching when the microparticles are manipulated and when an optical image is detected, which will be described later.
Next, a method for capturing fine particles will be described. The light oscillated from the light source 2 is collimated by a lens (not shown), passes through the polarizing beam splitter 3 and the quarter wavelength plate 8, passes through a condenser lens (not shown), and has a pure water (dispersion) 16 at the tip. Is incident on the optical fiber probe 4 immersed in.
The fine particles 15 dispersed in the medium are captured by the light emitted from the protruding portion 11 of the optical fiber probe 4. The material of the fine particles 15 is, for example, silica, gold, and an example of approximate dimensions is a diameter of several tens nm to several μm.
At the time of capturing, the optical fiber probe 4 is brought close to the sample plate 14 so that the condensing position of the light emitted from the protrusion 11, that is, the position where the light intensity is highest is arranged at the center of the microparticle 15. Move in the direction of separation. Information on the distance between the tip of the optical fiber probe 4 and the condensing position required at this time is obtained in advance through experiments or the like.
The above movement is performed by a probe control unit 6 attached to the optical fiber probe 4.
The probe control unit 6 is configured by, for example, a triaxial actuator or the like, and can move the optical fiber probe 4 in the direction in which the optical fiber probe 4 is moved closer to and away from the sample board 14 and in the horizontal direction.
Note that the probe controller 6 may move the sample plate 14 in the direction of approaching and separating from the optical fiber probe 4 instead of moving the optical fiber probe 4 in the direction of approaching and separating from the sample plate 14.

Next, the configuration of the optical fiber probe 4 will be described.
The optical fiber probe 4 includes an optical waveguide 10 and a protrusion 11. The optical waveguide unit 10 is configured by an optical fiber in which a cladding 13 is provided around a core 12.
The core 12 and the clad 13 are each made of silicon dioxide glass, and the structure is controlled so that the refractive index of the clad 13 is lower than that of the core 12 by adding germanium, phosphorus, or the like.
The protruding portion 11 is constituted by a core portion 9 protruding from the clad 13 at one end of the optical waveguide portion 10. As shown in FIG. 1, the protruding core portion 9 has a conical shape with a gradient that gradually tapers to the tip. Incidentally, this conical shape can be easily produced by chemical etching or the like.
An enlarged view of the optical fiber probe 4 in FIG. 1 is shown in FIG. Based on FIG. 2, the shape of the protrusion 11 of the optical fiber probe 4 will be described. Light 18 (hereinafter, propagated light) propagating in the core 12 reaches the optical fiber probe 4 and then exits from the optical fiber probe 4 through the protrusion 11.
In the present embodiment, the surface of the optical fiber probe 4, that is, the surface of the protruding core portion 9 has a conical taper shape, and the angle θ formed by the normal 20 of the surface of the core portion 9 and the optical axis 21 of the propagating light. (Hereinafter, the inclination angle θ) has a shape that is less than the total reflection angle in propagation light 18 and greater than 0 degrees.
Thereby, most of the propagation light 18 incident on the optical fiber probe 4 is emitted as refracted light to the outside of the optical fiber probe 4, and the emitted light is about several hundred nm to several μm from the tip of the optical fiber probe 4. A light spot having a high light intensity is formed by condensing at a distant position.
The phenomenon in which light is collected at a position away from the tip of the optical fiber probe 4 to form a light spot having a high light intensity is the case where the inclination angle θ is less than the total reflection angle in propagation light 18 and greater than 0 degrees. It is an inherent phenomenon.
In the conventional optical fiber probe in which the tilt angle θ is formed to be equal to or greater than the total reflection angle, the light intensity is highest near the tip of the optical fiber probe, and the light intensity rapidly decreases as the distance from the tip of the optical fiber probe increases. Only light spots with low light intensity could be formed.
On the other hand, if the inclination angle θ is formed to be less than the total reflection angle as in the present embodiment, the light is condensed at a position separated from the tip of the optical fiber probe 4 by several hundred nm to several μm. Thus, a light spot having a high light intensity can be formed.

Next, a method for observing the optical image of the position of the fine particles using the photodetector 1 of the present embodiment will be described.
The output control unit 7 shown in FIG. 1 oscillates light after adjusting the output from the light source 2 for optical image detection. Here, the output value switched by the output control unit 7 is set to several mW to several hundred mW when the fine particle is manipulated (captured), and is set to several tens μm to several hundred μm when the optical image is detected. At the time of optical image detection, the light spot by the above-mentioned weak light is generated on the sample board 14 to detect the image without capturing the fine particles.
The oscillated light passes through the polarization beam splitter 3 and enters the quarter-wave plate 8 in the same manner as when capturing the fine particles described above. The light that has passed through the quarter-wave plate 8 becomes circularly polarized light, passes through the core 12 of the optical fiber probe 4, and is emitted from the protrusion 11 to the sample plate 14.
The emitted light is reflected by the sample board 14 and returns to the optical fiber probe 4. This light again passes through the quarter-wave plate 8, becomes linearly polarized light different from the polarization direction of the light emitted from the light source 2, and enters the polarization beam splitter 3 again.
Since this incident light has different polarization directions in the process of passing through the quarter-wave plate 8, it is reflected by the polarization beam splitter 3 and guided to the photodetector 5.
In the optical system for capturing elementary particles described above, a normal beam splitter may be used as an alternative to the polarizing beam splitter 3.
The photodetector 5 can generate a luminance signal by receiving and photoelectrically converting the return light from the sample board 14. The probe control unit 6 described above generates a luminance signal while scanning the optical fiber probe 4 with respect to the sample board 14 in the horizontal direction, thereby obtaining a luminance signal image in the scanning range.
An image created based on the luminance signal generated by the photodetector 5 is displayed on a display device (not shown). The user can observe an optical image on the sample board 14 based on an image displayed on a display device (not shown). At this time, the position of the fine particles can also be confirmed from the optical image.
Further, when the optical image is observed, the spot diameter of the light spot described above can be changed by switching the wavelength of the light emitted from the light source 2 in the light wavelength conversion unit 17.

FIG. 3 is a diagram showing the transition of the light spot diameter at the condensing position when the wavelength of the propagating light is changed. FIG. 3 shows the light spot at the condensing position when the wavelength of the propagating light is changed. A transition example of the diameter is shown. Actually, the light wavelength emitted from the light source 2 is selected based on FIG. 3 in accordance with the required observation resolution.
In FIG. 3, since the spot width is on the order of submicron, high-resolution observation can be performed as compared with observation using a conventional optical microscope. With the above-described configuration and operation method, it is possible to manipulate fine particles and observe an optical image of the sample surface.
FIG. 4 is a schematic view showing a second embodiment of an optical trap device including an optical fiber probe according to the present invention. With reference to FIG. 4, the outline | summary and the operation process in the optical trap apparatus of 2nd Embodiment are demonstrated.
The light detection device 30 which is the optical trap device shown in the figure is different from the light detection device 1 shown in FIG. 1 in that the optical fiber probe 4 is covered with a light-shielding coating layer 19.
Even in the light detection device 30 configured as described above, the optical fiber probe 4 is provided, whereby the near-field optical image of the sample plate 14 can be observed.
Further, the light wavelength conversion section 17 emits light having a light wavelength matched to the light-shielding coating layer 19 from the light source 2, whereby fine particles with little energy loss can be captured. The method for capturing fine particles is the same as that described in the first embodiment, except that the light wavelength of the light emitted from the light source 2 is controlled based on the following conditions.
Regarding the wavelength of light emitted from the light source 2 at the time of capturing the fine particles, considering the dispersion characteristics of the complex refractive index of the light-shielding coating layer 19, and selecting the wavelength that sets the light transmittance to a maximum value or a value in the vicinity thereof, The light intensity of the light emitted from the optical fiber probe 4 can be improved. The control is performed by the optical wavelength conversion unit 17 described above.
FIG. 5 is a diagram showing a light transmittance distribution.
In general, the light transmittance distribution has a convex shape as shown in FIG. Here, the wavelength at which the light transmittance is a value in the vicinity of the maximum value means that the wavelengths when the light transmittance takes a value (T ₁ ) that is ½ of the maximum value T ₀ are λ ₁₁ and λ ₁₂ . In this case, the wavelength falls within the wavelength band (shaded area in FIG. 5) between the wavelengths λ _{11 and} λ ₁₂ . For example, in the case of gold (Au), it is desirable to select light having a wavelength that falls within a wavelength band of about 480 to 700 nm.

Next, the configuration and operation of the near-field optical image observation of the sample board 14 will be described.
Light having a linearly polarized light component emitted from the light source 2 passes through the polarizing beam splitter 3 and is incident on the optical fiber probe 4 after the polarization component is controlled by the quarter wavelength plate 8. The light incident on the optical fiber probe 4 is propagated through the core 12 as it is and is incident on the light-shielding coating layer 19 of the optical fiber probe 4. At this time, near-field light as an evanescent wave oozes out on the exit end side of the light-shielding coating layer 19. With the near-field light oozing, the probe controller 6 moves the optical fiber probe 4 toward the sample board 14.
At this time, when the distance between the tip of the optical fiber probe 4 and the sample board 14 is ¼ or less of the wavelength λ of the light emitted from the light source 2, the near-field light oozed from the optical fiber probe 4 is Irradiated on the board 14, a minute light spot is formed on the sample board 14 by near-field light. The near-field light that forms the light spot passes through the light-shielding coating layer 19 and is guided to the photodetector 5 through the core 12.
The photodetector 5 can generate a luminance signal by receiving and photoelectrically converting the return light from the sample board 14. The probe control unit 6 described above generates a luminance signal while causing the optical fiber probe 4 to scan the sample board 14 in the horizontal direction, thereby obtaining a luminance signal image in the scanning range.
An image created based on the luminance signal generated by the photodetector 5 is displayed on a display device (not shown). The user can observe an optical image on the sample board 14 based on an image displayed on a display device (not shown). At this time, the position of the fine particles can also be confirmed from the optical image.
In this way, when the near-field optical image observation of the sample board 14 is performed, a higher-resolution image observation can be performed as compared with the method described in the first embodiment, so that the size of the operation object is very small. In this case, it can be said that the configuration is particularly suitable for the order of several nm to several tens of nm.
Here, the light-shielding coating layer 19 may be made of any material, but an Au thin film can be obtained because it can provide an effect of enhancing near-field light by surface plasmons and is excellent in chemical stability. desirable. In the case of the Au thin film, by selecting the wavelength emitted from the light source 2, an effect of enhancing the near-field light can be obtained, and as a result, the near-field light generation efficiency and the S / N ratio can be improved.
In general, the wavelength at which the near-field light enhancement effect appears remarkably is, for example, about 500 to 600 nm in Au.

As described above, according to the photodetecting device 1 (30) of the present embodiment, by further providing a configuration capable of detecting the light applied to the sample, the optical trap of the micro object, the position of the micro object after the operation, An optical trap device that enables observation can be provided.
Also provided is an optical trap device that includes wavelength control means for controlling the wavelength of light incident on an optical fiber probe, and that enables observation of a minute object position with an appropriate measurement resolution by changing the light spot diameter. be able to.
In addition, by controlling the wavelength of the light incident on the optical fiber probe and detecting the light irradiated on the sample, the optical trap that enables high-resolution observation of the micro-object optical trap and the micro-object position after the operation. It is possible to provide a method.
By using an optical fiber probe capable of forming a condensed spot of emitted light and generating near-field light with a tapered structure, it is possible to manufacture a light trap of a micro object, operation, and position of the micro object after operation with a simple configuration. It is possible to provide an optical trap device that enables high-resolution observation.
Further, according to the present embodiment, the optical trap having a light loss due to the light shielding film is provided by including the wavelength control means for controlling the wavelength of the light incident on the optical fiber probe and using the light wavelength having a high light shielding film transmittance. An apparatus can be provided.
Furthermore, by using gold (Au) as the light-shielding film of the optical fiber probe, an optical trap device that enables optical trapping and manipulation of minute objects, high S / N and high-resolution observation of the minute object position after manipulation is provided. can do.
Furthermore, by setting the wavelength of light incident on the optical fiber probe to a light wavelength having a high light-shielding film transmittance, it is possible to provide an optical trap method with little light loss due to the light-shielding film.

1 is a schematic diagram illustrating a first embodiment of an optical trap device including an optical fiber probe according to the present invention. It is an enlarged view explaining the shape of the protrusion part of the optical fiber probe shown in FIG. It is a figure which shows transition of the light spot diameter in the condensing position at the time of changing the wavelength of propagation light. FIG. 3 is a schematic diagram showing a second embodiment of an optical trap device including an optical fiber probe according to the present invention. It is a figure which shows light transmittance distribution with a graph.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,30 Optical trap apparatus, 2 light source, 4 optical fiber probe, 5 photodetector, 6 probe control part (moving means), 10 optical waveguide part (optical fiber), 11a surface of protrusion part, 12 core, 13 clad, 14 Sample board, 17 Wavelength control means, 18 Propagating light, 19 Light-shielding coating layer, 20 Normal

Claims (11)

  A light source for emitting light, an optical fiber having a core for propagating light emitted from the light source, an optical fiber probe formed with an optical probe for emitting light to the tip of the core, and a minute object And a moving means for moving the sample disk relative to the optical fiber probe. The optical fiber probe has a conical shape and propagates through the optical fiber. An optical trap device, wherein an inclination angle of a normal line on a part or a whole surface of the optical fiber probe with respect to an optical axis of propagating light is less than a total reflection angle of the propagating light and larger than 0 degree.   2. The optical trap device according to claim 1, further comprising detection means for detecting light emitted from the optical probe onto the sample plate.   2. The optical trap according to claim 1, further comprising wavelength control means for controlling a wavelength of light emitted from the light source so that a size of a light spot by the emitted light becomes a desired value. apparatus.   Light is emitted from the light source, has a conical shape, and the inclination angle of the normal line on the surface or the entire surface of a part of the optical probe with respect to the optical axis of the propagating light propagating through the optical fiber is less than the total reflection angle of the propagating light The emitted light is propagated to the core of the formed optical fiber probe, and the light is so formed that a spot based on the propagated light propagated through the core is formed in the vicinity of a minute object arranged on the sample plate. The micro object is captured by moving the fiber probe relative to the surface to be measured and moved away from the surface to be measured, and the optical fiber probe is moved relative to the sample plate in the horizontal direction. Is moved relative to the sample plate.   5. The optical trap method according to claim 4, wherein a wavelength of light emitted from the light source is controlled to a wavelength determined based on a size of the light spot.   A light source for emitting light, an optical fiber having a core for propagating light emitted from the light source, and an optical probe for emitting light to the tip of the core are formed, and the optical probe is covered with a light-shielding coating layer An optical trap device comprising: an optical fiber probe; a sample plate for arranging a minute object; and a moving means for moving the sample plate relative to the optical fiber probe. The optical fiber probe has a conical shape. And the inclination angle of the normal line on the surface or the entire surface of a part of the optical fiber probe with respect to the optical axis of the propagation light propagating through the optical fiber is less than the total reflection angle of the propagation light and more than 0 degree An optical trap device that is large.   7. The optical trap device according to claim 6, further comprising detection means for detecting light emitted from the optical fiber probe to the sample board.   A wavelength control means for controlling the wavelength of light emitted from the light source so that the light transmittance of the light-shielding coating layer is a wavelength having a maximum value or a value in the vicinity thereof. Item 7. The optical trap device according to Item 6.   The optical trap device according to claim 6, wherein a material of the light-shielding coating layer is gold.   Light is emitted from the light source, has a conical shape, and the inclination angle of the normal line on the surface or part of the entire surface of the optical probe with respect to the optical axis of the propagation light propagating through the optical fiber is the total reflection angle of the propagation light. Protruding the emitted light to the core of an optical fiber probe formed at an angle of less than 0 degree and greater than 0 degrees, and a spot based on the propagated light propagated through the core is in the vicinity of a minute object disposed on the sample plate By moving the optical fiber probe relative to the surface to be measured so as to be close to and away from the surface to be measured, the micro object is captured and the optical fiber probe is moved horizontally with respect to the sample plate. The optical trap method is characterized in that the minute object is moved relative to the sample plate by moving the sample relative to the sample plate.   11. The optical trap method according to claim 10, wherein the wavelength of the light controlled by the wavelength control means is set to a wavelength at which the light transmittance of the light-shielding coating layer is a maximum value or a value in the vicinity thereof.

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